Flat roofs are everywhere. Most commercial, institutional, and industrial roofs are flat roofs. Thousands of millions of square feet of flat roof are installed each year. Flat roofs are expensive to install ($4 to $6 per SF or more for a new roof) and replacement roofs can cost as much as $8 to $10 per square foot when disposal costs of the old roof are included.
Roofs are often ignored as part of the building maintenance plan. The roof only gets attention when it makes itself known, and the only time that happens is when it leaks. Forty-five percent (45%) of all new roofs develop serious problems within one year of installation. The National Roofing Contractors Association estimates that the sources of the problems are due to:
50% – Poor workmanship
20% – Poor design
15% – Poor maintenance
10% – Material failures
Flat roofs are highly susceptible to leaks and water damage. Once a leak begins, it will saturate the insulation beneath it, diminishing the R-value of the ceiling’s insulation and adding unneeded heating and cooling costs to a building. Luckily, IR is a very quick and easy way to locate flat roof leaks!
Detecting the leak must be done at nighttime, typically a couple hours after the sun goes down. There also must be at least two or three days of no rain before the test can be completed.
Throughout the day the sun’s heat will warm the surface of the roof. The areas which contain water beneath the surface will warm up much slower than the rest of the roof area. The reason for this is because water has a higher thermal capacity than the surrounding insulation materials, and absorbs heat at a much slower rate.
At nighttime, after the sun goes down and the roof starts to cool off, the areas where moisture is trapped beneath will still be releasing the heat that was stored all day from the sun and can then be easily visible as “hot spots” when compared to the rest of the dry roof areas.